Introduction
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How has rock music changed over time?
Rock music has been a genre that has undergone lots of transformations since its start in the 1950s and 1960s. The evolution of rock music can be divided into several decades, including the 60s, 70s, 80s, 90s, and 00s. In this portfolio, I will be exploring how rock music changed during these decades, and what makes each decade unique.
Corpus
The corpus for this portfolio will be a selection of popular rock songs from each decade, chosen based on the top search result in Spotify. These songs have been put together into one playlist containing 432 tracks, totalling up to almost 30 hours of playtime. The corpus includes a mix of well known and lesser known tracks, and covers a variety of sub genres within the rock music genre.
Comparison Points
It is expected that there will be differences between each decade in terms of musical styles, instrumentation, and production techniques, but some similarities may also be present. For example, the use of guitar, bass, and drums as the core instruments in rock music has remained consistent throughout the years. This portfolio aims to explore the changes over time and provide a comprehensive overview of the history of rock music.
Track duration
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Trend in track duration
This plot displays the duration of 432 rock music tracks released over the period 1962 - 2009, with the x-axis indicating the year of release and the y-axis the track duration The plot also includes a trend line that shows a peak in 1982. Upon analyzing the plot, we can observe that there is a trend towards shorter song durations. If this trend continues, songs may become increasingly shorter in the future. It would be interesting to include more recent songs to see if this trend is still consistent with current rock music releases. This plot has significant implications for the music industry, as it highlights the evolving preferences of listeners towards shorter tracks. As such, it could be useful for music producers and artists in determining the optimal length of their tracks. One could say that the spread of songs also influences this trend line. The next tab shows the number of songs per year in the rock corpus.
Tracks per year
Like stated in the last tab, one could say that the spread of songs in the corpus could influence the mean and trend line of the track duration analysis. Taking a deeper look into this plot, we can see that the spread of songs is actually quite spread and randomized in terms of number of songs per year.
Tracks per decade
Finally, this plot shows the number of tracks per decade, which is an even stronger argument that the spread, in terms of decades, is randomized and spread in a good manner.
Prevalence of mode
Trend in track mode
Taking a closer look at the musical modes of songs, the plot depicts the number of songs in major and minor per decade. The right y-axis represents the ratio between major and minor songs in each decade. From the visualization, we observe a relatively stable ratio between the 1960s and the 1990s, hovering around 3, indicating that major songs outnumbered minor songs by three times. However, a noteworthy shift occurred in the 2000s, where the ratio gradually declined and fell below 2, implying a relatively higher proportion of minor songs compared to other decades. This phenomenon may be caused by several factors. One possibility is that there was a shift in popular music tastes during the 2000s, with a greater appreciation for minor key tonalities in mainstream music. Another possibility is that advancements in music technology and production techniques made it easier and more accessible for artists to experiment with and produce music in minor keys. Overall, this plot provides valuable insight into the trends and shifts in popular music over the past few decades and highlights the importance of considering both the quantitative and qualitative aspects of musical data analysis.
Visualizing this trend
Chromagram
Now let’s take a closer look at an individual song. This example shows the song “Bohemian Rhapsody” by Queen. On the right you can see a the chromagram of this song. A chromagram is a visual representation of the pitch content of a piece of music. It breaks down the frequencies of the notes played in the song and shows how much of each pitch is present at any given moment. The chromagram for “Bohemian Rhapsody” is particularly interesting because of the song’s intricate harmonies and layering of vocals and instruments.
The song, which was written by Freddie Mercury and released in 1975, is widely regarded as a masterpiece of rock music. Its unconventional structure, combining elements of rock, opera, and balladry, and its intricate harmonies and instrumentation, have made it a beloved classic and a staple of radio airplay and movie soundtracks.
“Bohemian Rhapsody” begins with a gentle piano introduction, gradually building in intensity with the addition of drums, bass, and guitar. Mercury’s powerful vocals enter with the first verse, setting the stage for the song’s complex narrative and emotional arc. The middle section of the song features a stunning a cappella vocal passage, showcasing the intricate harmonies and layering that are a hallmark of the Queen sound.
As the song progresses, the instrumentation and vocal arrangements continue to evolve and build, reaching a powerful climax with the famous “Galileo” section and the explosive guitar solo. The song then returns to its gentle opening piano melody, bringing the listener on a full emotional journey from soft and contemplative to bombastic and triumphant.
In summary, “Bohemian Rhapsody” is a testament to the creativity, innovation, and musicianship of the members of Queen. Its lasting popularity and influence on rock music make it an important part of any discussion of the genre, and its chromagram provides a fascinating glimpse into the song’s intricate musical elements.
Cepstrogram
Here we have another perspective on the song “Bohemian Rhapsody” by Queen. On the right you can see a cepstrogram showing the spectral content of the song over time. A cepstrogram is a type of spectrogram that displays the frequency spectrum of a signal, but with the added dimension of time. It can provide valuable insight into the complex harmonic structure and timbre of a piece of music.
Looking at the cepstrogram of “Bohemian Rhapsody,” we can see the complex interplay of harmonics and overtones that are a hallmark of the Queen sound. One interesting feature of the cepstrogram is the presence of multiple harmonics and overtones at different frequencies. This is due to the complex interplay of the different instruments and voices in the song, which create a rich and layered sound.
Furthermore, the cepstrogram shows a relatively high magnitude around 21 and 85 seconds into the song. This can be attributed to Freddie Mercury’s impressive vocal range and his sustained high notes on these timestamps, which are accompanied by intricate harmonies and instrumentation. The 21-second mark marks the beginning of the iconic a cappella section of the song, where Mercury’s voice is prominently featured in a complex arrangement of harmonies and counterpoints. The 85-second mark marks the beginning of Freddie’s solo, singing his famous “Mama”, which is one of the most memorable moments of the song.
Overall, the spectral content of “Bohemian Rhapsody” is constantly changing and evolving, reflecting the emotional arc of the lyrics and the dynamic shifts in instrumentation and vocal arrangements. The cepstrogram provides a fascinating glimpse into the complex harmonic and timbral elements of this classic rock song, showcasing the creativity and musicianship of the band members. As such, it is a valuable tool for understanding the song’s lasting popularity and influence on the genre of rock music.
